Unblock app deletion by falling back to noop when safe

[100mik]

Describe the problem/challenge you have
#1208 and #1220 introduced a fallback scenario, where Apps perform a loop delete to unblock themselves when they can do so safely. This however does not take into account multiple namespaces that might be terminating without owning any cluster resources.

Describe the solution you'd like
The same fallback mechanism should be used while dealing with Apps affecting multiple namespaces and not managing cluster resources.

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